I am trying to generate symbols +1,-1 using a function by partitioning the interval of the function into two levels. The function is the Tent Map. This in a way achieves bpsk modulation. I want to see the constellation diagram for bpsk . But I am getting error

$\begingroup$So, if your symbols are +1 and -1, why not just do plot([-1 1],[0 0],'x')?$\endgroup$
– MBazNov 29 '16 at 3:10

$\begingroup$Note the 'x' in my plot command. You really need to read the entire docs for plot. In general, you can do something like plot(real(C),imag(C),'x') where C is a complex array holding your constellation points.$\endgroup$
– MBazNov 29 '16 at 13:39

Actually, the QAM constellation contains all combinations of possible real and complex values. Hence, you need the cartesian product between real and complex parts. Taking this solution, you can plot the constellation diagram.